Physico-chemical, biological and heavy metal status of spent oil-contaminated soils in the vicinity of garages in and around Guwahati city, Assam, India

In this study, we analyse the impact of the indiscriminate spilling of spent oil by garages on the surrounding soils. Physico-chemical, biological and heavy metal (HM) profiles of the spent oil-contaminated soils were compared with control samples in Guwahati city, Assam, India. The results revealed that the spent oil-contaminated soils show an increase in the abundance of HMs (varying from 58 to 18,400 mg/kg), total oil and grease (77,000–161,000 mg/kg) and a decrease in bacterial load (68.2–76.2%) and enzymatic activities (18.02–98.4%) when com­pared with control samples. Site-specific remediation strategies are needed to mitigate this problem